The coast around the Abandoned Yellow River Delta changed a lot due to human activities. Using satellite images, researchers studied how the coastline, tidal flat area, and slope changed from 1984 to 2019. They created a new method to correct the coastline data and considered the impact of seawalls. The coast can be divided into parts eroding in the north and depositing in the south. Reclamation reduced tidal flat areas by 43% and 27% in the erosion and deposition parts, making the slopes steeper in the erosion part. The disappearance of the intertidal zone due to reclamation could harm habitats.